Expanded-metal lath



Jam.v 1'4, 1930.

1 J. w. PEARCE EXPANDED METAL LATH Filed Jan. 5', 1929 Mfg@ Q y FAU,

Patented. Jan. 14, 1,930

UNITED STATES vPATENT OFFICE JAMES W. PEABCE, OF PHILADELPHIA,`ZEIENNSYLVAIN'IZA, ASSIGNOR T0 NORTE WEST- EBN EXPANDED METAL COMPANY,F GHICAGD,A ILLINOIS, A CORPORATION OF ILLINOIS EXPANDED-HETAL LATEApplication med January 5, 1928. Serial No. 330,519.

Theinvention relates to improvements in expanded metal lath and methodof maln'ng the'same and it consists in the matters hereinafter describedand more particularly pointed p .5 out in the appended claims.

. The expanded metal lath with which my 1nventionis articularlyconcerned isof that type formecPl by.v operating upon a previouslyslitted sheetto bend or deiiect the strands toproduce the" open diamondmesh, the bent strands extending diagonally of the sheet in oppositedirections and being connected at their'intersections b bonds or bridgesdisposed in rows extending transversely of the Sheet.

' ln this type of lath the strands are not placed under'tension bystretching as in diamond mesh lath made by simultaneously slitting andstretching. the strands so that it may 2o be readily andadvantageouslymade from very light auge sheet metal. Lath of this kindheretdore generally accepted by the trade for the support of mortar andplaster coats in walls and ceilings, measures about 24 wide 25 and 96long and the slitted sheet from which it is produced measures 8" wide byabout 108 long. Such lath is furnished in diierent standard gaugesand'weights` namely 24,. 25, 2 6 and 27 gauge, which weighs about 3.4,3.0,

- 2.5 and 2.2 pounds per square yard respectively, the most popular'being the lightest gauge andweight, because greatervyarda e issecuredfor the same weight and purc ase price. Such sheets were slittedprevious to expansion to provide about one hundred and thirty strandsextending transversely of the sheet. Said bonds are about. twelvehundredths of an. inch wide and the strands are about six hundredths ofan inch wide. The bonds are spaced about seven eights of an inch` apartlongitudinally of the sheet so that there are about one hundred andtwenty four rows -of such bonds and strands.

As such sheets are expanded to about twenty four inches wide which isabout 'three times the original width, the transverse ing of the bondsinreach row will be a y ut three eighths inches apart. The abovementioned-lath represents the best form of open diamoild mesh lath whichthe manufacturers have heretofore` made and which the trade hascustomarily accepted as the mortar and plaster support in walls andceilings.

As a result of my study and research in this art,' I have discoveredthat the lath above mentioned has a number' of inherent objections. Forexample, with such lath it has been necessary for the plasterer to use arelatively dry mortar for the first coat. This requires the use of moremortar to properly cover the lath than is'necessary with a mortar of amore fluid 0r mushy consistency. Such relatively dry mortar is also morediicult to apply so that the area of lath covered in a predeterminedperiod of time is reduced. The natural inclination of the plasterer isto increase the fluidity of the mortar so thatit may be more` Veasilyapplied. Such practice howeverI embodies other and probably moreobjectionable features. That is to say when this more fluid mortar isused a very considerable portion thereof will pass through the meshunder trowelling and form large keys or gobs at the Arear of the lath,which slough of under their own weight. This not only results in a wasteof mortar but brings forth another objectionable condition. It will vbe'understood o v course that it is desired ,to obtain a at surface `toprovide a lath of this'kind which will have better mortar retainingualities in that the metal ofthe lath is distri uted in a` differentopen diamond mesh as well as the strands andrbonds are materiallyincreased.

Still another Objectof the invention is to im.v

provide a lath of this kind which is practical to make from a previouslyslitted sheet, upon -machines at present'in use without cha the sheetrectangular.

Fig.-.3 is a view in elevatlon on a full size scale of one cornerfragment of the sheet shown in Fi 1 with the correct proportion of 'theslits t ereinto define the vstrands and and 6 6 respectively of F'bonds.

Fig. 4 is a view of the fragment shown in Fi 3 after the same has beenexpanded.

igs. 5 and 6 are detail sectional views on an enlarged scale as taken onthe lines 5-5 In the present invention Igprovide a blank sheet o f metal1 of the desired gauge, weight and dimensions as heretofore employedwhich blank' approximates eight inches in width and one hundred andeight inches in length.

I operate upon said sheet in any-convenient lmanner to produce thereintransverse rows of slits 2 2 extending lengthwise of the sheet. Theserows of slits are so arranged Y that those in one row overlap and aredisposed between those of adjacent rows to form" transverse rows ofbonds or bridges 3 and 4 respectively the endmost bonds in eachalternate row being integralwith the selvage portions 5 5 of the sheet.

The areas between the overlaplping slits f define the strands 6-6 whichin t e finished sheet extend diagonally of the sheet and are f connectedat their intersections by the integral bonds 3 and 4 respectively, thestrands and bonds being disposed 'edgewise at an angle to the plane ofthe sheet.

In my improved lath the overlapping slits 1n one row are purposelyspaced closer t0- gether than heretofore, thus making the .strands 6-6about five-hundredths of an inch in width instead ofabout'six-hundredths as fore mentioned. This produces about one hundredand ift -siX strands in each transverse row instea o f one hundred andthutyas before mentioned. It is' apparent that 1n a .sheet of the sameunit area there is thus providedin each transverse row an increasednumber of strands amounting to about one-fifth more strands than in aslitted sheet whereinthe strands are six-hundredths of an inch wide.

I purposely arrange the bonds closer to-` gether so that the length ofthe strands are reduced in proportion to that extent whereby the numberof rows of slits lerngthwisel vin the sheet is increased in number toabout one hundred and forty-four. This represents an increase of aboutone sixth more rows than heretofore employed. By increasing fth andincreasing the number of rows of strands about one-slxth an increase instrands and bonds is afforded in the sheet of the same unit areaamounting to about one-third more than the number heretofore formed insuch a sheet.

Such a slitted sheet is then expanded in the usualmanner, as b theexpanding machines now in usc and w ich can be employed for this purposewithout change exceptreadjustment changes, Whensuch a sheet is expandedand trimmed in the usual manner it will have the same unit area asbefore mentioned and approximating twenty-four inches by ninety-sixinches.

It is pointedoutthat in the finished ex-V panded sheet as shown in Figs.4, 5 and 6 the bonds in each alternate tgansvers'e row 'extend edgewiseand perpendicularly to the plane of the sheet while the bonds 1n eachintermediate roware inclined and extend edgewise at an'angle of about 60to the plane of the sheet. This peculiar difference 1n angularity is dueto certain characteristics 1n the sheet itself after bein slit as Iforinstance with a particular type o slitting?. mechanismwhich forms nopart of the present invention.

` As .is well known in sheet lath of this kind, the stiffness of thesheet as represented by the tendency to flexcunder its own weight 1napplyingit in place upon the usual furringv strips as well as its actionin remaining flat when so applied, is-due tothe number of bonds providedand the relative angularlty of such bondsto the .plane of the sheet.

With my improved lath, with the same weight per unit area of sheet, themetal 1s distributed in amanner different from that heretofore'recognized as the only possible way.- Therefore, .a greater number ofbonds is provided in my improved sheet wlth the bonds .in one-half ofthe rows disposed edge- Wise and perpendicularly to the plane of thesheet and with the other'half disposed edgewise at the sixty degreeangle before menthe mmiber of strands in each row about 011etioned sothat the stiffness of the sheet is increased. .SuchA a sheet of coursehandles `aresmaller in area but greater in number anda greater` numberof mortar retardingV elements as defined by the strands and bonds arepresented. Such a lath better receives the mortar which may be used inthat mushy .consistency desired by the plasterers so that the same isbetter adapted for faster application and of a less depth or thicknessthan heretofore possible.

Again with an increased number of smaller mesh, together with anincreased number of retarding elements less motar is consumed `informing tlie'keys in the rear side of the lath and the keys are smallerand lighter in weight so that they do not slough off. Thus waste isreduced to a minimum as well as the objectionable pulling action onthose portions the length of a stranden two sides of the diamond meshbeing approximately threefourths lof an inch, alternate bonds being aplane at right angles to the plane of the vlath while the otheralternate bonds are at an acute angle to said plane.

In testimony whereof, I set my hand, this Srdday of J an., 1929.

r JAMES'W. PEARCE.

of the mortar line with the mesh or openings.

The thin coat of mortarmade practical by my improvedlath is indeeddesired by the plasterers because it is more economical and easierapplied and it dries or seasons quicker sothat less shifting ofscaffolding between coats is necessary. Actual tests disclose the mortarand plaster saving qualities of my improved lath.

It is pointed sions of the strands and bonds as well as the extent, thenumber thereofis increased about athird which indeed more thancompensates for the reduction mentioned so far as stiffness of thefinished lath is concerned.

With the increased number of strands `and bonds the lath is betterdistributed in the wall material which it more effectively retains andreinforces.

' While in describing the invention Iv have referred in detail tocertain dimensions, details of construction as well as form andaroutthat although the dimen- 'open diamond mesh is reduced to a certainrangement of the parts thereof, the same is to be considered purely asillustrative so that I do not wish to be limited theretoexcept as may bepointed out specifically inthe appended claims.

I claim as my invention: 1. A n improved mortar receivin and holding,expanded sheet metal diamon mesh lath, the strands of which areapproximately .05 inches in width and anu'mber of strands in eachvlongitudinal row of meshes being vapproximately 144 in a'lath v96inches along@ after the metal has been expanded. 1

2. Anim rovedmortarreceiving andhold- A Y' ing, expan ed sheet""meta1diamond shape strands, the strands'ofwhich are -a lath expandedtransversel p three to one', having bon connecting the matelyfive-hundredths inches in wi and -the len h of a strand on'twosides ofthe mesh being from center to centerdiamon of the bondsapproximately`three fourths ofanmch.

at the rate Of roxi- 3. An improved mortar receiving and Y holding,expanded sheet metal diamond shape three to one, having vbon rox-{ive-hundredths inches in wi have hereunto

